KR100635070B1 - Organic Electro-Luminescence device and method for fabricating of the same - Google Patents

Abstract

The present invention provides an organic electroluminescent device and a method of manufacturing the same, which reduce conductive defects such as contact resistance with a pixel electrode and disconnection of a pixel electrode by forming a conductive buffer layer on top of a source / drain electrode.

The present invention is an insulating substrate; A thin film transistor comprising a source / drain electrode having a semiconductor layer, a gate electrode, and a conductive buffer layer positioned on the insulating substrate; A passivation layer covering the thin film transistor on the entire surface of the substrate and having a first via hole through which the drain electrode is exposed; A reflection film formed on a predetermined portion of the passivation film; A pixel electrode covering the reflective film on the passivation film and connected to the exposed drain electrode; A pixel definition layer having an opening that exposes a predetermined portion of the pixel electrode; Forming an organic layer on the pixel electrode, the organic layer including at least a light emitting layer for emitting light; It provides an organic electroluminescent device comprising the step of forming an upper electrode positioned on the organic film layer and a manufacturing method thereof.

Organic electroluminescent element, reflective film, conductive buffer layer

Description

Organic electroluminescent device and its manufacturing method {Organic Electro-Luminescence device and method for fabricating of the same}

1 is a cross-sectional view of a conventional organic electroluminescent device.

FIG. 2 is an enlarged photograph of part A of FIG. 1.

3A to 3D are cross-sectional views of the organic electroluminescent device manufacturing process according to the present invention.

4A and 4B are cross-sectional views of a double-sided organic electroluminescent device manufacturing process according to another embodiment of the present invention.

 <Description of the symbols for the main parts of the drawings>

100: insulating substrate 180: source / drain electrode

190 conductive buffer layer 200 passivation film

201: first via hole 210: planarization film

202: second via hole 220: reflective film

230: pixel electrode 240: pixel defining layer

250: organic light emitting layer 260: upper electrode

The present invention relates to an organic electroluminescent device and a method of manufacturing the same, and more particularly, in order to solve the problem that damage of the drain electrode and undercut shape of the planarization film are generated in the process of etching the reflective film material. The organic electroluminescent element which forms a conductive buffer layer in this invention, and its manufacturing method are related.

With the advent of the high information age, there is an increasing demand for fast and accurate information in the hand, and the development of a display device that is light and thin, easy to carry, and has high information processing speed is rapidly being made. Conventional CRTs have high weight, volume, and power consumption, and LCDs have technical limitations on process complexity, narrow viewing angles, contrast ratios, and large area.

On the other hand, the organic electroluminescent device is self-luminous and does not require a backlight such as LCD, so it is not only lightweight but also simplifies the process, and has the advantages of low voltage driving, high luminous efficiency, wide viewing angle and fast response speed. As it is possible to realize high quality video, it is rapidly rising as a next generation display.

In general, organic electroluminescent devices are classified into passive matrix type and active matrix type according to driving method. Passive matrix type is easy to manufacture because its display area is composed of simple matrix type by anode and cathode. Due to problems such as rising driving voltage and lowering the life of the material, it is limited to low resolution and small display applications. On the other hand, in the active matrix method, the display area is equipped with a thin film transistor for each pixel to supply a constant current irrespective of the number of pixels of the organic light emitting display device, thereby showing stable luminance and low power consumption. It is advantageous for the application.

In addition, the organic EL device is classified into a bottom emission type and a top emission type or a double emission type according to a direction in which light generated from the organic emission layer is emitted. The bottom emission type emits light toward the formed substrate and is disposed on the organic emission layer. A reflective electrode is formed and a transparent electrode is formed below the organic light emitting layer. Here, when the organic electroluminescent device adopts an active matrix method, the area where the thin film transistor is formed may not transmit light, thereby reducing the area where light may be emitted. In the top emission type, since a transparent electrode is formed on the organic light emitting layer and a reflective electrode is formed on the organic light emitting layer, light is emitted in a direction opposite to the substrate side, and thus the luminance can be improved by increasing the area through which light passes.

In addition, the double-sided light emitting type is an organic electroluminescent device having both a main display window of a top emission type and an auxiliary display window of a bottom emission type, and demand is increasing rapidly according to the miniaturization and low power consumption of the device. The double-sided organic light emitting display device is mainly used in a mobile phone, an auxiliary display window is provided on the outside, and a main display window is provided on the inside.

1 is a cross-sectional view of a conventional organic electroluminescent device.

As shown in FIG. 1, a semiconductor layer 11, a gate insulating film 20, a gate electrode 21, an interlayer insulating film 30, a source 30a and a drain 30b are formed on a substrate 10 such as glass or plastic. A thin film transistor including a thin film transistor is formed, a passivation film 40 is formed on the thin film transistor, and a first via hole 45 for exposing a predetermined portion of the drain electrode 30b is formed.

Subsequently, after forming the planarization film 50 for planarizing the step by the thin film transistor on the passivation film 40, the second via hole 55 is formed in the portion where the first via hole 45 is formed. .

The reflective film 61 and the pixel electrode 62 are formed on the substrate on which the predetermined region of the drain electrode is exposed by the first via hole 45 and the second via hole 55, and the pixel is disposed on the pixel electrode. After the pixel definition layer 60 for separation is formed, an opening P for exposing a predetermined portion of the pixel electrode is formed.

An organic electroluminescent device is fabricated by forming an organic film 70 including at least an organic light emitting layer on the opening P over the entire surface of the substrate, and forming an upper electrode 80 thereon.

The organic electroluminescent device formed as described above has a role of reflecting light so that the light formed in the organic electroluminescent layer on the upper surface is a reflective film formed under the pixel electrode in a top emission manner.

FIG. 2 is an enlarged photograph of part A of FIG. 1.

As shown in FIG. 2, when the passivation film is etched to form a second via hole to expose a predetermined region of a lower drain electrode, and a reflective film material is formed on the entire surface of the substrate, the reflective film material is wet-etched to form a reflective film. In addition, the wet etching may not only etch the reflective film but also damage the surface of the exposed drain electrode, and cause an undercut phenomenon of the planarization film, which is an organic material, to cause disconnection during deposition of the pixel electrode.

The present invention is to solve the above-mentioned disadvantages and problems of the prior art, an organic material for wet etching the reflective film after forming a conductive buffer layer of a material resistant to the etching liquid wet etching the reflective film material on the drain electrode. An object of the present invention is to provide an electroluminescent device and a method of manufacturing the same.

In order to achieve the above technical problem, the present invention provides an organic electroluminescent device and a method of manufacturing the same, which reduce a defective rate such as disconnection when forming a pixel electrode by contacting the pixel electrode and forming a conductive buffer layer on the source / drain electrode. do.

The present invention is an insulating substrate; A thin film transistor comprising a semiconductor layer, a gate electrode, and a source / drain electrode having a conductive buffer layer on the insulating substrate; A passivation layer covering the thin film transistor on the entire surface of the substrate and having a first via hole through which the drain electrode is exposed; A reflection film formed on a predetermined portion of the passivation film; A pixel electrode covering the reflective film on the passivation film and connected to the exposed drain electrode; A pixel definition layer having an opening that exposes a predetermined portion of the pixel electrode; An organic layer including at least a light emitting layer for emitting light on the pixel electrode; It provides an organic electroluminescent device and a method of manufacturing the same, characterized in that it comprises an upper electrode located above the organic film layer.

The present invention also provides an insulating substrate having a first region and a second region; A plurality of thin film transistors each comprising a source / drain electrode having a semiconductor layer, a gate electrode, and a conductive buffer layer positioned on the insulating substrate in each of the first region and the second region; A passivation layer covering the thin film transistors on the entire surface of the substrate and having a plurality of first via holes exposed by the drain electrode; A reflective film patterned in the light emitting area on the passivation film of the first area; A pixel electrode connected to the exposed drain electrode on the passivation layer in each of the first region and the second region; A pixel definition layer having an opening that exposes a predetermined portion of the pixel electrode; An organic layer including at least a light emitting layer for emitting light on the pixel electrode; An organic electroluminescent device and a manufacturing method thereof are provided, including an upper electrode disposed on the organic layer.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3A to 3D are cross-sectional views of the manufacturing process of the organic EL device according to the present invention.

First, FIG. 3A is a cross-sectional view of a step of sequentially forming a semiconductor layer, a gate insulating film, a gate electrode, an interlayer insulating film, a source / drain electrode, a conductive buffer layer, and a passivation film on a substrate on which a predetermined element is formed.

As shown in FIG. 3A, a group consisting of a silicon oxide film, a silicon nitride film, and a silicon oxide film / silicon nitride film laminated film to prevent impurities flowing out from the insulating substrate 100 on the insulating substrate 100 having a predetermined element formed thereon. The buffer layer 110 selected from is formed. Subsequently, the semiconductor layer 120 including the source, drain, and channel regions is formed, and the gate insulating layer 130 is formed on the substrate on which the semiconductor layer is formed. Subsequently, the gate electrode 140 is formed in a predetermined region on the gate insulating layer 130, and the interlayer insulating layer 150 is formed to protect the gate electrode and the lower elements. Subsequently, after the gate insulating film and the interlayer insulating film are sequentially formed, via holes are formed so that the source / drain electrodes can be electrically connected to the source / drain regions, and then the via holes are filled with a conductive metal material. The drain electrode 180 and the conductive buffer layer 190 are sequentially formed. Subsequently, a passivation film 200 is formed on the entire surface of the substrate.

In this case, the source / drain electrode is formed of a metal containing Ag, Ag alloy, Mo, MoW and Mo alloy, the conductive buffer layer is one selected from the group consisting of ITO, IZO, Ti and Cu, such as resistive etching solution It is formed by sequentially stacking the materials on the front of the substrate with a conductive material of.

Next, FIG. 3B is a cross-sectional view illustrating a process of forming a first via hole for contacting a drain electrode in the passivation film, forming a planarization film on the substrate, and then forming a second via hole. As shown in FIG. 3B, a first via hole 201 is formed by dry etching using a photoresist pattern to connect a portion of the formed passivation layer 200 to a drain electrode and a pixel electrode. Since the first via hole is a region for contacting the drain electrode of the thin film transistor and the pixel electrode to be formed later, the first via hole is preferably formed to be as wide as possible in order to be easily electrically connected and to have a low connection resistance.

Subsequently, the planarization layer 210 is formed on the substrate on which the predetermined element is formed. The planarization layer not only removes the morphology of the substrate caused by the various elements formed, but also the lower elements are formed on the upper elements. It is electrically insulated from and formed to protect the lower elements. The planarization layer is etched by dry etching using a photoresist pattern to form the second via hole 202 in the region where the first via hole is formed to open the drain electrode. In this case, the second via hole must have a smaller cross-sectional area or the same as that of the first via hole.

In this case, the passivation film may be made of one material selected from the group consisting of a silicon oxide film, a silicon nitride film, and a silicon oxide film / silicon nitride film. In addition, the planarization film may be made of one material selected from the group consisting of acrylic resin, benzocyclobutene resin, polyimide resin and polyphenol resin.

Next, FIG. 3C is a cross-sectional view of the step of forming a reflective film on the substrate. As shown in FIG. 3C, a reflective film material such as aluminum or an aluminum alloy is formed on the planarization film on which the second via hole is formed. In this case, since a part of the drain electrode is exposed by the second via hole, the reflective film material is formed on the exposed conductive buffer layer 190.

Subsequently, a pattern (not shown) is formed on the reflective film material formed on the entire surface of the substrate and wet-etched to form the reflective film 220.

At this time, by forming a conductive buffer layer resistant to the etching liquid on the drain electrode, the exposed drain electrode is adversely affected by wet etching, that is, a problem of contact resistance with the pixel electrode due to damage of the drain electrode and undercut of the planarization layer. It prevents the disconnection of the pixel electrode due to the occurrence of the phenomenon.

Next, FIG. 3D is a cross-sectional view illustrating a process of forming a pixel electrode, an organic light emitting layer, and an upper electrode on the substrate.

As shown in FIG. 3D, the drain electrode exposed by the via hole and the pixel electrode 230 connected to the metals of the double layers 180 and 190 of the conductive buffer layer are patterned.

The pixel electrode 230 may be an ITO including a reflective film, a transparent electrode made of IZO, or a reflective electrode selected from the group consisting of Pt, Au, Ir, Cr, Mg, Ag, Ni, Al, and alloys thereof.

It is preferable to form a pixel defining layer 240 having an opening P exposing a part of the surface of the pixel electrode on the pixel electrode. The pixel defining layer having the opening P serves to define a light emitting area. Here, the pixel defining layer is preferably formed of one material selected from the group consisting of acrylic resin, benzocyclobutene (BCB) and polyimide (PI).

Subsequently, an organic layer 250 including at least an organic light emitting layer is formed on the entire surface of the substrate including the pixel electrode 230 exposed in the opening P.

The organic layer may further include at least one of a hole injection layer, a hole transport layer, a hole suppression layer, an electron transport layer and an electron injection layer.

An upper electrode is formed on the organic layer 250.

Here, the upper electrode 260 is a transparent electrode made of ITO or IZO, or light is transmitted through a selected metal material made of Pt, Au, Ir, Cr, Mg, Ag, Ni, Al, and alloys thereof. Form thinly.

Hereinafter, another embodiment of the present invention will be described in detail with reference to the accompanying drawings.

4A and 4B are cross-sectional views of a double-sided organic electroluminescent device manufacturing process according to the present invention.

For reference, an insulation substrate is provided, and a first region B1 and a second region B2 are defined in the insulation substrate. For reference, in the manufacturing process of the double-sided organic electroluminescent device, all the processes except for the reflective film forming process are performed simultaneously in the first region B1 and the second region B2.

4A is a cross-sectional view of a step of sequentially forming a semiconductor layer, a gate insulating film, a gate electrode, an interlayer insulating film, a source / drain electrode, a conductive buffer layer, a passivation film having via holes, and a planarization film on an insulating substrate.

First, FIG. 4A illustrates a silicon oxide film, a silicon nitride film, and a silicon oxide film / silicon to prevent impurities flowing out from the insulating substrate 300 on an insulating substrate defined as a first region B1 and a second region B2. A buffer layer 310 selected from the group consisting of laminated films of nitride films is formed. Subsequently, a semiconductor layer 320 including a source, a drain, and a channel region is formed, and a gate insulating layer 330 is formed on the substrate on which the semiconductor layer is formed. Subsequently, the gate electrode 340 is formed in a predetermined region on the gate insulating layer 330, and the interlayer insulating layer 350 is formed to protect the gate electrode and the lower elements. Subsequently, after the gate insulating film and the interlayer insulating film are sequentially formed, via holes are formed so that the source / drain electrodes can be electrically connected to the source / drain regions, and then the via holes are filled with a conductive metal material. The drain electrode 380 and the conductive buffer layer 390 are sequentially formed. Subsequently, a passivation film 400 is formed on the entire surface of the substrate.

At this time, the source / drain electrode is formed of a metal containing Ag, Ag alloy, Mo, MoW and Mo alloy, the conductive buffer layer is one selected from the group consisting of ITO, IZO, Ti and Cu, such as resistive etching solution It is formed by sequentially stacking the materials on the front of the substrate with a conductive material of.

Subsequently, a first via hole (401 of FIG. 4B) is formed by dry etching using a photoresist pattern to electrically connect a portion of the formed passivation layer 400 to the drain electrode and the pixel electrode. Since the first via hole is a region for contacting the drain electrode of the thin film transistor and the pixel electrode to be formed later, the first via hole is preferably formed to be as wide as possible in order to be easily electrically connected and to have a low connection resistance.

Subsequently, the planarization layer 410 is formed on the substrate on which the predetermined element is formed. The planarization layer not only removes the morphology of the substrate caused by the various elements formed, but also the lower elements are formed on the upper elements. It is electrically insulated from and formed to protect the lower elements. The planarization layer is etched by dry etching using a photoresist pattern in a region where the first via hole is formed to open the drain electrode, thereby forming a second via hole 402. In this case, the second via hole must have a smaller cross-sectional area or the same as that of the first via hole.

In this case, the passivation film may be made of one material selected from the group consisting of a silicon oxide film, a silicon nitride film, and a silicon oxide film / silicon nitride film. In addition, the planarization film may be made of one material selected from the group consisting of acrylic resin, benzocyclobutene resin, polyimide resin and polyphenol resin.

Next, FIG. 4B is a cross-sectional view illustrating a process of forming a reflective film, a pixel electrode, an organic light emitting layer, and an upper electrode on the substrate.

A reflective film material such as aluminum or an aluminum alloy is formed on the planarization film on which the second via hole is formed. Here, the reflective film is formed only in the first region. In this case, since a part of the drain electrode is exposed by the second via hole, the reflective film material is formed on the exposed conductive buffer layer 390.

Subsequently, a pattern (not shown) is formed on the reflective film material formed on the entire surface of the substrate and wet-etched to form the reflective film 420.

At this time, by forming a conductive buffer layer resistant to the etching liquid on the drain electrode, the exposed drain electrode is adversely affected by wet etching, that is, a problem of contact resistance with the pixel electrode due to damage of the drain electrode and undercut of the planarization layer. It prevents the disconnection of the pixel electrode due to the occurrence of the phenomenon.

Subsequently, the drain electrode exposed by the via hole and the pixel electrode 430 connected to the metal of the double layer 380 and 390 of the conductive buffer layer are patterned.

The pixel electrode 430 may be formed of a transparent electrode made of ITO or IZO.

It is preferable to form a pixel defining layer 440 having an opening P exposing a part of the surface of the pixel electrode on the pixel electrode. The pixel defining layer having the opening P serves to define a light emitting area. Here, the pixel defining layer is preferably formed of one material selected from the group consisting of acrylic resin, benzocyclobutene (BCB) and polyimide (PI).

Subsequently, an organic layer 450 including at least an organic light emitting layer is formed on the entire surface of the substrate including the pixel electrode 430 exposed in the opening P.

The organic layer may further include at least one of a hole injection layer, a hole transport layer, a hole suppression layer, an electron transport layer and an electron injection layer.

Subsequently, an upper electrode 460 is formed on the organic layer. The upper electrode is formed of a transparent electrode or a transparent metal electrode in the first region B1, and is formed of a transparent electrode or a reflective electrode in which a reflective film is stacked in the second region B2.

Although the present invention has been shown and described with reference to preferred embodiments as described above, it is not limited to the above-described embodiments and those skilled in the art without departing from the spirit of the present invention. Various changes and modifications will be possible.

Therefore, in the method of forming a semiconductor device of the present invention, when the drain electrode opened by the first via hole and the second via hole forms a reflective film by wet etching, the conductive electrode layer is formed by forming a conductive buffer layer on the drain electrode. By preventing the undercut of the planarization film which may cause disconnection when the pixel electrode is deposited without damage to the surface, it is possible to solve the contact resistance with the pixel electrode and reduce the defective rate during the process.

Claims (22)

An insulating substrate; A thin film transistor comprising a semiconductor layer, a gate electrode, and a source / drain electrode having a conductive buffer layer on the insulating substrate; A passivation layer covering the thin film transistor on the entire surface of the substrate and having a first via hole through which the drain electrode is exposed; A reflection film formed on a predetermined portion of the passivation film; A pixel electrode covering the reflective film on the passivation film and connected to the exposed drain electrode; A pixel definition layer having an opening that exposes a predetermined portion of the pixel electrode; An organic layer including at least a light emitting layer for emitting light on the pixel electrode; And an upper electrode positioned above the organic layer. The method of claim 1, The conductive buffer layer is an organic electroluminescent device, characterized in that made of a conductive material resistant to etching liquid. The method of claim 1, The conductive buffer layer is an organic electroluminescent device, characterized in that made of one conductive material selected from the group consisting of ITO, IZO, Ti and Cu. The method of claim 1, The source / drain electrode is made of one material selected from a metal material consisting of Ag, Ag alloy, Mo, MoW and Mo alloy. The method of claim 1, The organic electroluminescent device further comprises a planarization film on top of the passivation film. The method of claim 5, The flattening film is an organic electroluminescent device, characterized in that formed of one organic material selected from the group consisting of acrylic resin, polyimide resin, benzocyclobutene resin. The method of claim 1, The reflective film is an organic electroluminescent device, characterized in that formed of one metal selected from the group consisting of Al, Al alloys, Ag and Ag alloys. The method of claim 1, The upper electrode is an organic electroluminescent device, characterized in that consisting of a cathode or an anode. The method of claim 1, The upper electrode may be a transparent electrode made of ITO or IZO, or may be formed thin enough to transmit light with a selected metal material made of Pt, Au, Ir, Cr, Mg, Ag, Ni, Al, and alloys thereof. An organic electroluminescent element. The method of claim 1, The organic layer is an organic electroluminescent device comprising at least one of a hole injection layer, a hole transport layer, a hole suppression layer, an electron transport layer and an electron injection layer. Providing an insulating substrate; Forming a thin film transistor including a source / drain electrode including a semiconductor layer, a gate electrode, and a conductive buffer layer on the insulating substrate; Stacking a passivation film on the entire surface of the substrate including the thin film transistor and forming a first via hole for exposing the drain electrode; Forming a reflective film on a predetermined portion of the passivation film; Forming a pixel electrode in contact with the source / drain electrode through the first via hole; Forming a pixel defining layer covering the source / drain electrode and the pixel electrode and forming an opening for exposing the pixel region; Forming an organic layer on the pixel electrode, the organic layer including at least a light emitting layer for emitting light; And forming an upper electrode on the organic film layer. An insulating substrate having a first region and a second region; A plurality of thin film transistors each comprising a source / drain electrode having a semiconductor layer, a gate electrode, and a conductive buffer layer positioned on the insulating substrate in each of the first region and the second region; A passivation layer covering the thin film transistors on the entire surface of the substrate and having a plurality of first via holes exposed by the drain electrode; A reflective film patterned in the light emitting area on the passivation film of the first area; A pixel electrode connected to the exposed drain electrode on the passivation layer in each of the first region and the second region; A pixel definition layer having an opening that exposes a predetermined portion of the pixel electrode; An organic layer including at least a light emitting layer for emitting light on the pixel electrode; And an upper electrode positioned above the organic layer. The method of claim 12, The conductive buffer layer is an organic electroluminescent device, characterized in that made of a conductive material resistant to etching liquid. The method of claim 12, The conductive buffer layer is an organic electroluminescent device, characterized in that made of one conductive material in the group consisting of ITO, IZO, Ti and Cu. The method of claim 12, The source / drain electrode is made of one material selected from a metal material consisting of Ag, Ag alloy, Mo, MoW and Mo alloy. The method of claim 12, The organic electroluminescent device further comprises a planarization film on top of the passivation film. The method of claim 16, The flattening film is an organic electroluminescent device, characterized in that formed of one organic material selected from the group consisting of acrylic resin, polyimide resin, benzocyclobutene resin. The method of claim 12, The reflective film is an organic electroluminescent device, characterized in that formed of one metal selected from the group consisting of Al, Al alloys, Ag and Ag alloys. The method of claim 12, The pixel electrode is an organic electroluminescent device, characterized in that consisting of a transparent electrode made of ITO or IZO. The method of claim 12, The upper electrode is an organic electroluminescent device, characterized in that the first region is made of a transparent electrode or a transparent metal electrode, and the second region is made of a transparent electrode or a reflective electrode laminated with a reflective film. The method of claim 12, The organic layer is an organic electroluminescent device further comprising at least one of a hole injection layer, a hole transport layer, a hole suppression layer, an electron transport layer and an electron injection layer. Providing an insulating substrate having a first region and a second region; Forming a plurality of thin film transistors each having a source layer and a drain electrode having a semiconductor layer, a gate electrode, and a conductive buffer layer on the insulating substrate, the first region and the second region; Forming a passivation layer covering the thin film transistors on the entire surface of the substrate and having a plurality of first via holes exposed by the drain electrode; Patterning and forming a reflective film provided in the light emitting region on the passivation film of the first region; Forming a pixel electrode connected to the exposed drain electrode on the passivation layer in each of the first region and the second region; Forming a pixel definition layer having an opening that exposes a predetermined portion of the pixel electrode; Forming an organic layer on the pixel electrode, the organic layer including at least a light emitting layer for emitting light; And forming an upper electrode on the organic film layer.

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